The present invention relates to a waste water filtration tank for the treatment of raw waste water.
Before waste water can be passed to processing plants such as water treatment facilities, all the solid waste within the effluent must be removed. It is known to use filtration tanks in order to remove such material, with the waste material being separated from the water before the water is either passed on for further processing or else, in some instances, discharged back into the river or sea. Other known methods of treatment include sand filtration and chemical treatment of the liquid to remove impurities.
It is the aim of the present invention to provide an automatic waste water flushing system which filters out solids from the effluent before automatically removing said solids from the tank, thereby allowing the filtration to be carried out with the minimum of supervision and also removing the need for the filtered solids to be discharged manually.
According to the present invention, there is provided a waste water tank for the filtering of solids from effluent, said tank comprising filtration means and automatic discharge means, wherein said discharge means discharges the filtered solids when said filter reaches a predetermined degree of contamination.
Preferably, said tank further comprises an inlet and first and second chambers, said filtration means being located between said inlet and said first chamber. Preferably, said effluent enters said inlet under hydrostatic pressure.
Preferably, said tank further comprises a reservoir which communicates with said inlet and each of said first and second chambers.
Preferably, said reservoir has a discharge outlet which moves between open and closed states under the action of said discharge means.
Preferably, said filtration means is a mesh screen adapted to prevent solids of a predetermined size from entering said first chamber from said reservoir.
Preferably, said tank is adapted so that liquid flows into said second chamber from said reservoir when said screen reaches said predetermined level of contamination.
Preferably, said discharge means comprises a float located within said second chamber, a gate covering said outlet, and operating means for the operation of said gate, wherein said float acts on said operating means when the level of liquid in said second chamber reaches a predetermined level.
Preferably, said operating means comprises a pivotable beam member, first and second rod members having first and second cams attached thereto, a flanged sleeve member attached to said gate, and a locking means, wherein said beam member and said first and second rod members are attached to said float, and wherein said beam member and said first and second rod members are adapted to communicate the movement of said float to said gate. Preferably, said operating means further comprises biasing means which forces said gate into the open position.
Preferably, said locking means comprises a pair of spring-loaded latches adapted to move between open and closed positions, said closed position being when said latches act on said flanged sleeve member and said open position being when said latches move away from said sleeve member under the action of said first and second cams, said gate opening under the action of said biasing means.
A preferred embodiment of the present invention will now be described, with reference to the accompanying drawings, in which: